You've got a lot of good advice already, particularly about keeping your perks combat-related until you can stand on your own, and learning the tricks of the trade.
I tend to prefer 1H and light armor, so I always put my perks in 1H, light armor, and archery at first. Use the 1/5 base perks, first, only branching into the specialties when you've
got a solid base. Remember that, even without perks in the sneak tree, you still do double damage when you attack from sneak. At early levels, that means a nice, slow, careful archery
shot from a distance, and maybe another if you can get it in time, before you put your bow away and slug it out.
If you have the first word of Unrelenting Force, that is a great opener to stagger them and buy you a moment of time to attack. If not, the quick shield bash is your best shot, though it
eats up a lot of stamina at first. Quick shield bash is holding the shield up and then tapping attack. Once you have a bash perk, there's another version but IMO it takes too long to wind
up, and they're not there by the time it fires. Don't worry about power attacks at first, but focus on "the dance." What you do is move in close and watch them prepare to attack, then
back out, let them swing and miss, and move back in to attack. The more you see them, you'll get an idea how soon you can start moving back in to maximize your time before they can
attack again, but that's when your shield bash buys you an extra second to attack. It's also good to circle right or left, so they have to move to hit you.
If you have the stamina left for a power attack, use the tap + tap and hold combo. Do this quickly, tap, release and then immediately hold again. It will give you a combination attack, of
a horizontal swipe followed by an immediate downward power chop. At early levels, some daggers can do as much damage as swords. The Elven dagger, for example, does the same
base damage (8) as the steel sword, but it moves more quickly. (1.3 dagger vs 1 sword vs .7 2H sword)
If you don't have a shield, or want more damage, keep fire in the off hand and give them a quick burst right before you swing your weapon. You can also block and set enemies on fire with a
standard torch, used the same way you would a shield.
The single most helpful things, for me, have been the paralysis potion and the atronach.
Most alchemy, as was mentioned, is quite weak at early levels, but paralysis can do wonders, even at the low-level, 3 second, strength, because it immediately disrupts their attack
and knocks them down. You can have many free shots, while they try to get back up, and you can always re-poison your weapon, if need be. Paralysis is made from any two of
canis root, imp stool, or swamp fungal pod, among others which are harder to obtain. Canis root and imp stool can be bought from the alchemists, for relatively little money.
(If I remember correctly, in the single digit prices) I always carry as many as I can get my hands on, in addition to healing potions.
Also, if you give your follower a few healing potions, they will take them when their health gets low.
The flame atronach is my second best friend. I always put my first point into health, then alternate between health and magicka, until I have enough magicka to cast a flame
atronach. You can buy the books from the court mages. If you want to cast sooner, don't sell your novice hood from Helgen, and it can be put on to cast an atronach before
combat, then just put your helmet back on and go.
About the only other useful thing I could say is, if you want an Elven dagger, take the carriage to Winterhold, then walk out of town on the main road. Be careful, as there may be
some wolves or something along the road. Outside of town, along the road, there is a mine with a single Winterhold guard out front. To your immediate left, down in the snow, is
a round Nordic ruin, called Journeyman's nook. There is one bandit inside, along with the corpse of a college mage, who will have a named Elven dagger. The intended quest was
never put into the game, so there's no reason not to use the dagger for your own purposes. It will hit like a steel sword but faster. Come to think of it, there's also an alchemy
table in case you run across some canis root and imp stool in your travels.
If you want some safer practice/exercise, travel to the Western Watchtower. Go into the field, behind and to the left of the tower (viewed from the road) and there's usually
something going on, with bandits, mages, wolves, etc. You can take them on or bait them and retreat toward the tower, where the guards will lend a hand.